The present invention relates generally to fiber optical arrays, and particularly, but not by way of limitation, to 3-dimentional array fiber optical couplers.
There is an increased requirement in industry for parallel optical transmission systems employing semiconductor lasers. This requirement in turn requires the provision of devices to couple laser light sources with fiber-optic transmission devices. The coupler of the present invention, will interface with arrayed designs that include Vertical Cavity Surface Emitting Lasers (VCSELs), laser diodes, detectors, etc. One major requirement of the coupler is that all individual fibers must be very precisely located so that proper alignment maximizes light transmission through the fibers.
Other objects and advantages will become apparent from the following disclosure.
The invention achieves solutions to the problems discussed above by providing a stacked coupler for an optical fiber array comprising:
Top(16) and bottom (10) plates, each substantially a rectangular prism having first and second substantially parallel major surfaces, wherein each said first surface has first (12) and second (14) substantially parallel grooves formed therein, and wherein said plates are disposed such that the respective grooves oppose; first and second side plates walls (20), each of said plates walls formed substantially as a rectangular prism having first and second major surfaces, a length, and bottom and top edges parallel to said length, wherein said bottom edge of said first wall is disposed within said first groove of said base-plate, said top edge of said first wall is disposed within said first groove of said top-plate, said bottom edge of said second wall is disposed within said second groove of said base-plate, said top edge of said second wall is disposed within said second groove of said top-plate, wherein each said first surface has a plurality of ferrule grooves (22) formed therein, and wherein each said second surface has at least one pin groove (24) formed therein, said pins are disposed such that said ferrule grooves oppose; a plurality of ferrules (30), formed substantially as a rectangular prism having first and second ends and first and second substantially parallel ferrule surfaces, wherein each said ferrule surface has a plurality of substantially parallel fiber grooves (32) formed therein, wherein said fiber grooves are spaced at a substantially constant pitch (34); and wherein said ends are disposed within said ferrule grooves; and a plurality of retaining plates (40), formed substantially as a rectangular prism having top and bottom substantially parallel major surfaces, wherein said retaining plates are disposed parallel to and interlaced with said ferrules and said top and bottom plates.
An aspect of the invention provides two means of maintaining the optical fibers in precise registration. In a first means, silicon pieces are fabricated to close tolerances to provide for fiber registration. In a second means, a retaining plate, preferably of an elastomeric material, forces the fibers against the substantially non-deformable silicon pieces.
An aspect of the invention provides a silicon ferrule having a precise array of parallel V-grooves formed therein for containing optical fibers. Furthermore, an elastomeric retaining plate forces the fibers to remain in said grooves.
An aspect of the invention provides precise alignment of the fibres without requiring . . .
An aspect of the invention provides an optical coupler having a relatively small horizontal footprint. According to this aspect, the fiber array is divided into a plurality of vertically-stacked subarrays.
According to another aspect of the invention, accumulation of tolerance error brought about by stacking multiple silicon pieces is reduced or eliminated by providing spacer bars.
According to another aspect of the invention, the array of parallel V-grooves is formed to have a substantially constant pitch. The pitch being defined as the center-to-center spacing of the grooves.
According to a further aspect of the invention, the centers of the V-grooves of a first subarray are in register with the centers of the V-grooves of its neighboring subarrays.
According to a further aspect of the invention, the registration of the V-grooves of a first array is offset with respect to its neighboring subarray by a constant fraction of a period. By way of non-limiting example, the registration of neighboring subarrays may be shifted by one half period.
Still other objects and advantages of the present invention will become readily apparent by those skilled in the art from the following detailed description, wherein it is shown and described preferred embodiments of the invention, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, without departing from the invention. Accordingly, the description is to be regarded as illustrative in nature and not as restrictive.